If you’re one of the millions of Americans who use escalators each year, you are probably deeply familiar with the vertical grooves that cover each stair. Few of us have stopped to consider why they exist in the first place, though. In fact, it’s one of the everyday things we take for granted, like these scientific mysteries.
Sure, the deep, grey lines make an escalator’s metal stairs more appealing to the eye. But those grooves serve a more functional purpose than you originally thought.
Anyone who has ridden an elevator knows that the steps perpetually circulate from the top to the bottom. However, here’s what you may not have noticed: As an escalator’s steps flatten, its ridged yellow lip—also called the comb plate—sweeps away any trash or litter that might have fallen on the stairs. The grooves lock the step and comb plate together, which makes it harder for any hazardous materials to slide underneath the lip and cause the escalator to stall, or worse: break down completely. By the way, here’s why walking up the escalator steps isn’t any faster.
That’s not the only reason why the grooves were created, though. They’re also a good place for liquids to pool together, protecting you from a nasty fall on the slick surface.
So the next time you step on an escalator, take a moment to appreciate those metal grooves. They exist to make sure you get to your office meeting on time. Now that you’re one fact smarter, learn more delightful hidden meanings of everyday objects.